Organometallic compound, organic light-emitting device including the organometallic compound, and diagnostic composition including the organometallic compound

ABSTRACT

An organometallic compound represented by Formula 1: 
     
       
         
         
             
             
         
       
         
         
           
             wherein, in Formula 1, groups and variables are the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2017-0127762, filed on Sep. 29, 2017, in the Korean IntellectualProperty Office, and all the benefits accruing therefrom under 35 U.S.C.§ 119, the content of which is incorporated herein in its entirety byreference.

BACKGROUND 1. Field

One or more embodiments relate to an organometallic compound, an organiclight-emitting device including the organometallic compound, and adiagnostic composition including the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices, whichhave superior characteristics in terms of a viewing angle, a responsetime, a brightness, a driving voltage, and a response speed, and whichproduce full-color images.

A typical organic light-emitting device includes an anode, a cathode,and an organic layer disposed between the anode and the cathode, whereinthe organic layer includes an emission layer. A hole transport regionmay be disposed between the anode and the emission layer, and anelectron transport region may be disposed between the emission layer andthe cathode. Holes provided from the anode may move toward the emissionlayer through the hole transport region, and electrons provided from thecathode may move toward the emission layer through the electrontransport region. The holes and the electrons recombine in the emissionlayer to produce excitons. These excitons transit from an excited stateto a ground state, thereby generating light.

Meanwhile, luminescent compounds may be used to monitor, sense, ordetect a variety of biological materials including cells and proteins.An example of the luminescent compounds includes a phosphorescentluminescent compound.

Various types of organic light emitting devices are known. However,there still remains a need in OLEDs having low driving voltage, highefficiency, high brightness, and long lifespan.

SUMMARY

Aspects of the present disclosure provide an organometallic compound, anorganic light-emitting device including the organometallic compound, anda diagnostic composition including the organometallic compound.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

An aspect of the present disclosure provides an organometallic compoundrepresented by Formula 1:

In Formula 1,

M may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca),titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn),gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium(Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold(Au),

X₁ to X₄ may each independently be C or N,

X₅ may be O, S, B(R′), N(R′), P(R′), C(R′)(R″), Si(R′)(R″), Ge(R′)(R″),C(═O), B(R′)(R″), N(R′)(R″), or P(R′)(R″),

two bonds selected from a bond between X₂ and M, a bond between X₃ andM, and a bond between X₄ and M may each be a coordinate bond, and theother thereof may be a covalent bond,

a bond between X₅ and M may be a covalent bond,

rings CY₁ to CY₄ may each independently be selected from a C₅-C₃₀carbocyclic group and a C₁-C₃₀ heterocyclic group,

T₁ may be selected from a single bond, a double bond,*—N[(L₆₁)_(a61)-(R₆₁)]—*′, *—B(R₆₁)—*′, *—P(R₆₁)—*′, *—C(R₆₁)(R₆₂)—*′,*—Si(R₆₁)(R₆₂)—*′, *—Ge(R₆₁)(R₆₂)—*′, *—S—*′, *—Se—*′, *—O—*′,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₁)═*′, *═C(R₆₁)—*′,*—C(R₆₁)═C(R₆₂)—*′, C(═S)—*′, and *—C≡C—*′,

T₂ may be selected from a double bond, *—N[(L₆₃)_(a63)-(R₆₃)]—*′,*—B(R₆₃)—*′, *—P(R₆₃)—*′, *—Si(R₆₃)(R₆₄)—*′, *—Ge(R₆₃)(R₆₄)—*′, *—S—*′,*—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₃)═*′,*═C(R₆₃)—*′, *—C(R₆₃)═C(R₆₄)—*′, *—C(═S)—, and *—C≡C—*′, T₃ may beselected from a single bond, a double bond, *—N[(L₆₅)_(a65)-(R₆₅)]—*′,*—B(R₆₅)—*′, *—P(R₆₅)—*′, *—C(R₆₅)(R₆₆)—*′, *—Si(R₆₅)(R₆₆)—*′,*—Ge(R₆₅)(R₆₆)—*′, *—S—*′, *—Se—*′, *—O—*′, *(═O)*′*—S(═O)—*′,*—S(═O)₂—*′, *—C(R₆₅)═*′, *═C(R₆₅)—*′, *—C(R₆₅)═C(R₆₆)—*′, C(═S)—*′, and*—C≡C—*′,

L₆₁, L₆₃, and L₆₅ may each independently be selected from a single bond,a substituted or unsubstituted C₅-C₃₀ carbocyclic group, and asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

a61, a63, and a65 may each independently be selected from 1 to 3,wherein, when a61 is two or more, two or more groups L₆₁ may beidentical to or different from each other, when a63 is two or more, twoor more groups L₆₃ may be identical to or different from each other, andwhen a65 is two or more, two or more groups L₆₅ may be identical to ordifferent from each other,

R₆₁ and R₆₂, R₆₃ and R₆₄, and R₆₅ and R₆₆ may each optionally be linkedvia a single bond, a double bond, or a first linking group to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group,

R₁ to R₄, R₆₁ to R₆₆, R′, and R″ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxylic acid group or a salt thereof, a sulfonic acid groupor a salt thereof, a phosphoric acid group or a salt thereof, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₇-C₆₀alkylaryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstitutedC₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀heteroarylthio group, a substituted or unsubstituted C₂-C₆₀heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀alkylheteroaryl group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂),—Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉),

a1 to a4 may each independently be an integer from 0 to 20,

two of a plurality of neighboring groups R₁ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of a plurality of neighboring groups R₂ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of a plurality of neighboring groups R₃ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

two of a plurality of neighboring groups R₄ may optionally be linked toform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group,

at least two neighboring groups selected from R₁ to R₄ may optionally belinked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group,

* and *′ each indicate a binding site to a neighboring atom,

at least one substituent of the substituted C₅-C₃₀ carbocyclic group,the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₇-C₆₀ alkylaryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₇-C₆₀arylalkyl group, the substituted C₁-C₆₀ heteroaryl group, thesubstituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀heteroarylthio group, the substituted C₂-C₆₀ heteroarylalkyl group, thesubstituted C₂-C₆₀ alkylheteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group,a hydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkylgroup, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀alkylheteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅),—B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),and

Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independentlybe selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from a C₁-C₆₀ alkyl group and aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkyl heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.

Another aspect of the present disclosure provides an organiclight-emitting device including:

a first electrode;

a second electrode; and

an organic layer disposed between the first electrode and the secondelectrode, wherein the organic layer includes an emission layer, andwherein the organic layer includes at least one organometallic compound.

The organometallic compound may act as a dopant in the emission layer.

Another aspect of the present disclosure provides a diagnosticcomposition including at least one organometallic compound representedby Formula 1.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of an organic light-emitting device accordingto an embodiment; and

FIG. 2 is a graph showing time-luminance relationships of organiclight-emitting devices manufactured according to Example 1 andComparative Example 1.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list.

It will be understood that when an element is referred to as being “on”another element, it can be directly in contact with the other element orintervening elements may be present therebetween. In contrast, when anelement is referred to as being “directly on” another element, there areno intervening elements present.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer, orsection from another element, component, region, layer, or section.

Thus, a first element, component, region, layer, or section discussedbelow could be termed a second element, component, region, layer, orsection without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that theterms “comprises” and/or “comprising,” or “includes” and/or “including”when used in this specification, specify the presence of statedfeatures, regions, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

In an embodiment, an organometallic compound is provided. Theorganometallic compound according to an embodiment is represented byFormula 1 below:

M in Formula 1 may be beryllium (Be), magnesium (Mg), aluminum (Al),calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu),zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru),rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt),or gold (Au).

For example, M may be Pt, Pd, or Au, but embodiments of the presentdisclosure are not limited thereto.

X₁ to X₄ in Formula 1 may each independently be C or N.

For example, in Formula 1,

i) X₂ and X₃ may each be N, and X₄ may be C; or

ii) X₂ and X₄ may each be N, and X₃ may be C, but embodiments of thepresent disclosure are not limited thereto.

X₅ in Formula 1 may be O, S, B(R′), N(R′), P(R′), C(R′)(R″), Si(R′)(R″),Ge(R′)(R″), C(═O), B(R′)(R″), N(R′)(R″), or P(R′)(R″). R′ and R″ are thesame as described herein.

For example, X₅ may be O or S, but embodiments of the present disclosureare not limited thereto.

In Formula 1, two bonds selected from a bond between X₂ and M, a bondbetween X₃ and M, and a bond between X₄ and M may each be a coordinatebond, the other thereof may be a covalent bond, and a bond between X₅and M may be a covalent bond. Therefore, the organometallic compoundrepresented by Formula 1 may be electrically neutral.

For example, in Formula 1,

i) the bond between X₂ and M and the bond between X₃ and M may each be acoordinate bond, and the bond between X₄ and M may be a covalent bond;or

ii) the bond between X₂ and M and the bond between X₄ and M may each bea coordinate bond, and the bond between X₃ and M may be a covalent bond,but embodiments of the present disclosure are not limited thereto.

In Formula 1, ring CY₁ to ring CY₄ may each independently be selectedfrom a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group.

For example, ring CY₁ to ring CY₄ may each independently a benzenegroup, a naphthalene group, an anthracene group, a phenanthrene group, atriphenylene group, a pyrene group, a chrysene group, a cyclopentadienegroup, a 1,2,3,4-tetrahydronaphthalene group, a thiophene group, a furangroup, an indole group, a benzoborol group, a benzophosphole group, anindene group, a benzosilole group, a benzogermole group, abenzothiophene group, a benzoselenophene group, a benzofuran group, acarbazole group, a dibenzoborole group, a dibenzophosphole group, afluorene group, a dibenzosilole group, a dibenzogermole group, adibenzothiophene group, a dibenzoselenophene group, a dibenzofurangroup, a dibenzothiophene 5-oxide group, a 9H-fluorene-9-on group, adibenzothiophene 5,5-dioxide group, an azaindole group, an azabenzoborolgroup, an azabenzophosphole group, an azaindene group, an azabenzosilolegroup, an azabenzogermole group, an azabenzothiophene group, anazabenzoselenophene group, an azabenzofuran group, an azacarbazolegroup, an azadibenzoborole group, an azadibenzophosphole group, anazafluorene group, an azadibenzosilole group, an azadibenzogermolegroup, an azadibenzothiophene group, an azadibenzoselenophene group, anazadibenzofuran group, an azadibenzothiophene 5-oxide group, anaza-9H-fluorene-9-on group, an azadibenzothiophene 5,5-dioxide group, apyridine group, a pyrimidine group, a pyrazine group, a pyridazinegroup, a triazine group, a quinoline group, an isoquinoline group, aquinoxaline group, a quinazoline group, a phenanthroline group, apyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isoxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzoxadiazole group, a benzothiadiazole group, a5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinolinegroup.

In an embodiment, ring CY₁ to ring CY₄ may each independently beselected from i) a 5-membered ring, ii) a 6-membered ring, iii) acondensed ring condensed with two or more 6-membered rings, and iv) acondensed ring condensed with at least one 5-membered ring and at leastone 6-membered ring.

The 5-membered ring may be selected from a cyclopentadiene group, afuran group, a thiophene group, a pyrrole group, a silole group, anoxazole group, an isoxazole group, an oxadiazole group, an isoxadiazolegroup, an oxatriazole group, an isoxatriazole group, a thiazole group,an isothiazole group, a thiadiazole group, an isothiadiazole group, athiatriazole group, an isothiatriazole group, a pyrazole group, animidazole group, a triazole group, a tetrazole group, an azasilolegroup, a diazasilole group, and a triazasilole group.

The 6-membered ring may be selected from an adamantane group, anorbornane group, a norbornene group, a cyclohexane group, a cyclohexenegroup, a benzene group, a pyridine group, a pyrimidine group, a pyrazinegroup, a pyridazine group, and a triazine group, but embodiments of thepresent disclosure are not limited thereto.

In Formula 1,

T₁ may be selected from a single bond, a double bond,*—N[(L₆₁)_(a61)-(R₆₁)]—*′, *—B(R₆₁)—*′, *—P(R₆₁)—*′, *—C(R₆₁)(R₆₂)—*′,*—Si(R₆₁)(R₆₂)—*′, *—Ge(R₆₁)(R₆₂)—*′, *—S—*′, *—Se—*′, *—O—*′,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₁)═*′, *═C(R₆₁)—*′,*—C(R₆₁)═C(R₆₂)—*′, *—C(═S)—*′, and *—C≡C—*′,

T₂ may be selected from a double bond, *—N[(L₆₃)_(a63)-(R₆₃)]—*′,*—B(R₆₃)—*′, *—P(R₆₃)—*′, *—Si(R₆₃)(R₆₄)—*′, *—Ge(R₆₃)(R₆₄)—*′, *—S—*′,*—Se—*′, *—O—, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₃)═*′,*═C(R₆₃)—*′, *—C(R₆₃)═C(R₆₄)—*′, *—C(═S)—*′, and *—C≡C—*′,

T₃ may be selected from a single bond, a double bond,*—N[(L₆₅)_(a65)-(R₆₅)]—*′, *—B(R₆₅)—*′, *—P(R₆₅)—*′, *—C(R₆₅)(R₆₆)—*′,*—Si(R₆₅)(R₆₆)—*′, *—Ge(R₆₅)(R₆₆)—*′, *—S—*′, *—Se—*′, *—O—*′,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₅)═*′, *═C(R₆₅)—*′,*—C(R₆₅)═C(R₆₆)—*′, *—C(═S)—*′, and *—C≡C—*′.

L₆₁, L₆₃, and L₆₅ may each independently be selected from a single bond,a substituted or unsubstituted C₅-C₃₀ carbocyclic group, and asubstituted or unsubstituted C₁-C₃₀ heterocyclic group.

For example, L₆₁, L₆₃, and L₆₅ may each independently be selected from:

a single bond, a benzene group, a naphthalene group, an anthracenegroup, a phenanthrene group, a triphenylene group, a pyrene group, achrysene group, a cyclopentadiene group, a furan group, a thiophenegroup, a silole group, an indene group, a fluorene group, an indolegroup, a carbazole group, a benzofuran group, a dibenzofuran group, abenzothiophene group, a dibenzothiophene group, a benzosilole group, adibenzosilole group, an azafluorene group, an azacarbazole group, anazadibenzofuran group, an azadibenzothiophene group, an azadibenzosilolegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a triazine group, a quinoline group, an isoquinolinegroup, a quinoxaline group, a quinazoline group, a phenanthroline group,a pyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isoxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzoxadiazole group, and a benzothiadiazole group; and

a benzene group, a naphthalene group, an anthracene group, aphenanthrene group, a triphenylene group, a pyrene group, a chrysenegroup, a cyclopentadiene group, a furan group, a thiophene group, asilole group, an indene group, a fluorene group, an indole group, acarbazole group, a benzofuran group, a dibenzofuran group, abenzothiophene group, a dibenzothiophene group, a benzosilole group, adibenzosilole group, an azafluorene group, an azacarbazole group, anazadibenzofuran group, an azadibenzothiophene group, an azadibenzosilolegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a triazine group, a quinoline group, an isoquinolinegroup, a quinoxaline group, a quinazoline group, a phenanthroline group,a pyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isoxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzoxadiazole group, and a benzothiadiazole group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a naphthyl group, a pyridinyl group, a pyrimidinyl group,a triazinyl group, a fluorenyl group, a dimethylfluorenyl group, adiphenylfluorenyl group, a carbazolyl group, a phenylcarbazolyl group, adibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group,a dimethyldibenzosilolyl group, a diphenyldibenzosilolyl group,—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),and

Q₃₁ to Q₃₉ may each independently be selected from:

—CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃,—CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CH₃, —CD₂CD₂H, and —CD₂CDH₂;

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, aniso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenylgroup, and a naphthyl group; and

an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butylgroup, a sec-butyl group, a tert-butyl group, an n-pentyl group, aniso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenylgroup, and a naphthyl group, each substituted with at least one selectedfrom deuterium, a C₁-C₁₀ alkyl group, and a phenyl group, butembodiments of the present disclosure are not limited thereto.

a61, a63, and a65 each indicate the number of L₆₁, L₆₃, and L₆₅, and mayeach independently be an integer from 1 to 3. When a61 is two or more,two or more of groups L₆₁ may be identical to or different from eachother, when a63 is two or more, two or more of groups L₆₃ may beidentical to or different from each other, and when a65 is two or more,two or more of groups L₆₅ may be identical to or different from eachother.

R₆₁ and R₆₂, R₆₃ and R₆₄, and R₆₅ and R₆₆ may each optionally be linkedvia a single bond, a double bond, or a first linking group, to therebyform a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group. The firstlinking group may be selected from *—N(R₉)—*′, *—B(R₉)—*′, *—P(R₉)—*′,*—C(R₉)(R₁₀)—*′, *—Si(R₉)(R₁₀)—*′, *—Ge(R₉)(R₁₀)—*′, *—S—*′, *—Se—*′,*—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₉)═, *═C(R₉)—*′,*—C(R₉)═C(R₁₀)—*′, *—C(═S)—*′, and *—C≡C—*′, wherein R₉ and R₁₀ are thesame as described in connection with R₁, and * and *′ each indicate abinding site to a neighboring atom.

In an embodiment, in Formula 1, T₁ and T₃ may each independently asingle bond, and T₂ may be *—N[(L₆₃)_(a63)-(R₆₃)]—*′, *—B(R₆₃)—*′,*—P(R₆₃)—*′, *—Si(R₆₃)(R₆₄)—*′, *—Ge(R₆₃)(R₆₄)—*′, *—S—*′, or *—O—*′,but embodiments of the present disclosure are not limited thereto.

In Formula 1, R₁ to R₄, R₆₁ to R₆₆, R′, and R″ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₇-C₆₀alkylaryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstitutedC₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀heteroarylthio group, a substituted or unsubstituted C₂-C₆₀heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀alkylheteroaryl group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂),—Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), wherein Q₁ to Q₉ arethe same as described above.

For example, R₁ to R₄, R₆₁ to R₆₆, R′, and R″ may each independently beselected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,—SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,—CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkylgroup, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acycloctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a biphenyl group, a naphthyl group,a pyridinyl group, and a pyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acycloctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a biphenyl group, a C₁-C₂₀ alkyl, aphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group;

a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, acycloctyl group, an adamantanyl group, a norbornanyl group, anorbornenyl group, a cyclopentenyl group, a cyclohexenyl group, acycloheptenyl group, a phenyl group, a biphenyl group, a C₁-C₂₀ alkyl, aphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenylgroup, an anthracenyl group, a fluoranthenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group,a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group,an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolylgroup, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, atriazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinylgroup, and an imidazopyrimidinyl group, each substituted with at leastone selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cycloctyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a cyclopentenyl group, acyclohexenyl group, a cycloheptenyl group, a phenyl group, a biphenylgroup, a C₁-C₂₀ alkyl, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group; and

—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), and

Q₁ to Q₉ are the same as described above.

In an embodiment, R₁ to R₄, R₆₁ to R₆₆, R′, and R″ may eachindependently be selected from hydrogen, deuterium, —F, a cyano group, anitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groupsrepresented by Formulae 9-1 to 9-19, and groups represented by Formulae10-1 to 10-194, but embodiments of the present disclosure are notlimited thereto:

In Formulae 9-1 to 9-19 and 10-1 to 10-194, “*” indicates a binding siteto a neighboring atom, “Ph” indicates a phenyl group, and “TMS”indicates a trimethylsilyl group.

In Formula 1, a1 to a4 each indicate the number of R₁ to R₄, and mayeach independently be an integer from 0 to 20 (for example, an integerfrom 0 to 4). When a1 is two or more, two or more of groups R₁ may beidentical to or different from each other, when a2 is two or more, twoor more of groups R₂ may be identical to or different from each other,when a3 is two or more, two or more of groups R₃ may be identical to ordifferent from each other, and when a4 is two or more, two or more ofgroups R₄ may be identical to or different from each other.

In an embodiment, in Formula 1, a moiety represented by

may be represented by one of Formulae CY1-1 to CY1-25:

In Formulae CY1-1 to CY1-25,

X₁ and R₁ are the same as described herein,

X₁₁ may be C(R₁₁)(R₁₂), N(R₁₁), O, S, or Si(R₁)(R₁₂),

R₁₁ to R₁₈ are the same as described in connection with R₁,

a16 may be an integer from 0 to 6,

a14 may be an integer from 0 to 4,

a13 may be an integer from 0 to 3,

a12 may be an integer from 0 to 2,

*′ indicates a binding site to M in Formula 1, and

* indicates a binding site to T₁ in Formula 1.

In one or more embodiments, a group represented by

in Formula 1 may be selected from groups represented by Formulae CY2-1to CY2-29:

In Formulae CY2-1 to CY2-29,

X₂ and R₂ are the same as described herein,

X₂₁ may be C(R₂₁)(R₂₂), N(R₂₁), O, S, or Si(R₂₁)(R₂₂),

X₂₃ may be C(R₂₃) or N,

X₂₄ may be O(R₂₄) or N,

R₂₁ to R₂₈ are the same as described in connection with R₂,

a25 may be an integer from 0 to 5,

a24 may be an integer from 0 to 4,

a23 may be an integer from 0 to 3,

a22 may be an integer from 0 to 2,

* indicates a binding site to T₁ in Formula 1,

*′ indicates a binding site to M in Formula 1, and

*″ indicates a binding site to T₂ in Formula 1.

In one or more embodiments, a group represented by

in Formula 1 may be selected from groups represented by Formulae CY3-1to CY3-29:

In Formulae CY3-1 to CY3-29,

X₃ and R₃ are the same as described herein,

X₃₁ may be C(R₃₁)(R₃₂), N(R₃₁), O, S, or Si(R₃₁)(R₃₂),

X₃₃ may be C(R₃₃) or N,

X₃₄ may be C(R₃₄) or N,

R₃₁ to R₃₈ are the same as described in connection with R₃,

a35 may be an integer from 0 to 5,

a34 may be an integer from 0 to 4,

a33 may be an integer from 0 to 3,

a32 may be an integer from 0 to 2,

*″ indicates a binding site to T₂ in Formula 1,

*′ indicates a binding site to M in Formula 1, and

* indicates a binding site to T₃ in Formula 1.

In one or more embodiments, a group represented by

in Formula 1 may be selected from groups represented by Formulae CY4-1to CY4-45:

In Formulae CY4-1 to CY4-45,

X₄ and R₄ are the same as described herein,

X₄₁ may be C(R₄₁)(R₄₂), N(R₄₁), O, S, or Si(R₄₁)(R₄₂),

X₄₃ may be C(R₄₃) or N,

X₄₄ may be C(R₄₄) or N,

X₄₅ may be C(R₄₅) or N,

R₄₁ to R₄₈ are the same as described in connection with R₄,

a46 may be an integer from 0 to 6,

a45 may be an integer from 0 to 5,

a44 may be an integer from 0 to 4,

a43 may be an integer from 0 to 3,

a42 may be an integer from 0 to 2,

* indicates a binding site to T₃ in Formula 1, and

*′ indicates a binding site to M in Formula 1.

In one or more embodiments, in Formula 1,

a moiety represented by

may be selected from groups represented by Formulae CY1(1) to CY1(22),and/or

a moiety represented by

may be selected from groups represented by Formulae CY2(1) to CY2(30),and/or

a moiety represented by

may be selected from groups represented by Formulae CY3(1) to CY3(30),and/or

a moiety represented by

may be selected from groups represented by Formulae CY4(1) to CY4(50),but embodiments of the present disclosure are not limited thereto:

In Formulae CY1(1) to CY1(22), CY2(1) to CY2(30), CY3(1) to CY3(30), andCY4(1) to CY4(50),

X₁ to X₄ and R₁ to R₄ are the same as described herein,

X₂₁ may be C(R₂₁)(R₂₂), N(R₂₁), O, S, or Si(R₂₁)(R₂₂),

X₃₁ may be C(R₃₁)(R₃₂), N(R₃₁), O, S, or Si(R₃₁)(R₃₂),

X₄₁ may be C(R₄₁)(R₄₂), N(R₄₁), O, S, or Si(R₄₁)(R₄₂),

R_(1a) to R_(1d) are the same as described in connection with R₁,

R_(2a) to R_(2c), R₂₁, and R₂₂ are the same as described in connectionwith R₂,

R_(3a) to R_(3c), R₃₁, and R₃₂ are the same as described in connectionwith R₃,

R_(4a) to R_(4d), R₄₁, and R₄₂ are the same as described in connectionwith R₄,

R₁ to R₄, R_(1a) to R_(1d), R_(2a) to R_(2c), R_(3a) to R_(3c), andR_(4a) to R_(4d) are not hydrogen, in Formulae CY1(1) to CY1(22), *′indicates a binding site to M in Formula 1, and * indicates a bindingsite to T₁ in Formula 1,

in Formulae CY2(1) to CY2(30), * indicates a binding site to T₁ inFormula 1, *′ indicates a binding site to M in Formula 1, and *″indicates a binding site to T₂ in Formula 1,

in Formulae CY3(1) to CY3(30), *″ indicates a binding site to T₂ inFormula 1, *′ indicates a binding site to M in Formula 1, and *indicates a binding site to T₃ in Formula 1, and

in Formulae CY4(1) to CY4(50), * indicates a binding site to T₃ inFormula 1, and *′ indicates a binding site to M in Formula 1.

In one or more embodiments, the organometallic compound may berepresented by Formula 1A:

In Formula 1A,

M, X₁ to X₅, and T₁ to T₃ are the same as described herein,

Y₁₁ may be C(Z₁₁) or N, Y₁₂ may be C(Z₁₂) or N, Y₁₃ may be C(Z₁₃) or N,Y₁₄ may be C(Z₁₄) or N, Y₂₁ may be C(Z₂₁) or N, Y₂₂ may be C(Z₂₂) or N,Y₂₃ may be C(Z₂₃) or N, Y₃₁ may be C(Z₃₁) or N, Y₃₂ may be C(Z₃₂) or N,Y₃₃ may be C(Z₃₃) or N, Y₄₁ may be C(Z₄₁) or N, Y₄₂ may be C(Z₄₂) or N,Y₄₃ may be C(Z₄₃) or N, and Y₄₄ may be C(Z₄₄) or N,

Z₁₁ to Z₁₄ are the same as described in connection with R₁, at least twoof Z₁ to Z₁₄ may optionally be linked to form a C₅-C₃₀ carbocyclic groupthat is unsubstituted or substituted with at least one R_(10a) or aC₁-C₃₀ heterocyclic group that is unsubstituted or substituted with atleast one R_(10a),

Z₂₁ to Z₂₃ are the same as described in connection with R₂, at least twoof Z₂₁ to Z₂₃ may optionally be linked to form a C₅-C₃₀ carbocyclicgroup that is unsubstituted or substituted with at least one R_(10a) ora C₁-C₃₀ heterocyclic group that is unsubstituted or substituted with atleast one R_(10a),

Z₃₁ to Z₃₂ are the same as described in connection with R₃, at least twoof Z₃₁ to Z₃₄ may optionally be linked to form a C₅-C₃₀ carbocyclicgroup that is unsubstituted or substituted with at least one R_(10a) ora C₁-C₃₀ heterocyclic group that is unsubstituted or substituted with atleast one R_(10a),

Z₄₁ to Z₄₄ are the same as described in connection with R₄, at least twoof Z₄₁ to Z₄₄ may optionally be linked to form a C₅-C₃₀ carbocyclicgroup that is unsubstituted or substituted with at least one R_(10a) ora C₁-C₃₀ heterocyclic group that is unsubstituted or substituted with atleast one R_(10a), and

R_(10a) is the same as described in connection with R₁.

For example, in Formula 1A, Y₁₁ may be C(Z₁₁), Y₁₂ may be C(Z₁₂), Y₁₃may be C(Z₁₃), Y₁₄ may be C(Z₁₄), Y₂₁ may be C(Z₂₁), Y₂₂ may be C(Z₂₂),Y₂₃ may be C(Z₂₃), Y₃₁ may be C(Z₃₁), Y₃₂ may be C(Z₃₂), Y₃₃ may beC(Z₃₃), Y₄₁ may be C(Z₄₁), Y₄₂ may be C(Z₄₂) or N, Y₄₃ may be C(Z₄₃),and Y₄₄ may be C(Z₄₄) or N, but embodiments of the present disclosureare not limited thereto.

In Formula 1, i) two of a plurality of neighboring groups R₁ mayoptionally be linked to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup, ii) two of a plurality of neighboring groups R₂ may optionally belinked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group, iii) two ofa plurality of neighboring groups R₃ may optionally be linked to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, iv) two of a plurality ofneighboring groups R₄ may optionally be linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, v) at least two neighboring groups selectedfrom R₁ to R₄ may optionally be linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, vi) two of Z₁₁ to Z₁₄ may optionally belinked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group, vii) two ofZ₂₁ to Z₂₃ may optionally be linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, viii) two of Z₃₁ to Z₃₃ may optionally belinked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic groupor a substituted or unsubstituted C₁-C₃₀ heterocyclic group, and ix) twoof Z₄₁ to Z₄₄ may optionally be linked to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group.

For example, i) the substituted or unsubstituted C₅-C₃₀ carbocyclicgroup or the substituted or unsubstituted C₁-C₃₀ heterocyclic group,formed by linking two of the plurality of neighboring groups R₁, ii) thesubstituted or unsubstituted C₅-C₃₀ carbocyclic group or the substitutedor unsubstituted C₁-C₃₀ heterocyclic group, formed by linking two of theplurality of neighboring groups R₂, iii) the substituted orunsubstituted C₅-C₃₀ carbocyclic group or the substituted orunsubstituted C₁-C₃₀ heterocyclic group, formed by linking two of theplurality of neighboring groups R₃, iv) the substituted or unsubstitutedC₅-C₃₀ carbocyclic group or the substituted or unsubstituted C₁-C₃₀heterocyclic group, formed by linking two of the plurality ofneighboring groups R₄, v) the substituted or unsubstituted C₅-C₃₀carbocyclic group or the substituted or unsubstituted C₁-C₃₀heterocyclic group, formed by linking at least two of R₁ to R₄, vi) thesubstituted or unsubstituted C₅-C₃₀ carbocyclic group or the substitutedor unsubstituted C₁-C₃₀ heterocyclic group, formed by linking two of Z₁₁to Z₁₄, vii) the substituted or unsubstituted C₅-C₃₀ carbocyclic groupor the substituted or unsubstituted C₁-C₃₀ heterocyclic group, formed bylinking two of Z₂₁ to Z₂₃, viii) the substituted or unsubstituted C₅-C₃₀carbocyclic group or the substituted or unsubstituted C₁-C₃₀heterocyclic group, formed by linking two of Z₃₁ to Z₃₃, and ix) thesubstituted or unsubstituted C₅-C₃₀ carbocyclic group or the substitutedor unsubstituted C₁-C₃₀ heterocyclic group, formed by linking two of Z₄₁to Z₄₄, may each independently be selected from:

a pentadiene group, a cyclohexane group, a cycloheptane group, anadamantane group, a bicyclo-heptane group, a bicyclo-octane group, abenzene group, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a naphthalene group, an anthracene group, a tetracenegroup, a phenanthrene group, a dihydronaphthalene group, a phenalenegroup, a benzothiophene group, a benzofuran group, an indene group, anindole group, a benzosilole group, an azabenzothiophene group, anazabenzofuran group, an azaindene group, an azaindole group, and anazabenzosilole group; and

a pentadiene group, a cyclohexane group, a cycloheptane group, anadamantane group, a bicyclo-heptane group, a bicyclo-octane group, abenzene group, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, a naphthalene group, an anthracene group, a tetracenegroup, a phenanthrene group, a dihydronaphthalene group, a phenalenegroup, a benzothiophene group, a benzofuran group, an indene group, anindole group, a benzosilole group, an azabenzothiophene group, anazabenzofuran group, an azaindene group, an azaindole group, and anazabenzosilole group, each substituted with at least one R_(10a), butembodiments of the present disclosure are not limited thereto.

R_(10a) is the same as describe in connection with R₁.

The terms “an azaindole group, an azabenzoborol group, anazabenzophosphole group, an azaindene group, an azabenzosilole group, anazabenzogermole group, an azabenzothiophene group, anazabenzoselenophene group, an azabenzofuran group, an azacarbazolegroup, an azadibenzoborole group, an azadibenzophosphole group, anazafluorene group, an azadibenzosilole group, an azadibenzogermolegroup, an azadibenzothiophene group, an azadibenzoselenophene group, anazadibenzofuran group, an azadibenzothiophene 5-oxide group, anaza-9H-fluorene-9-on group, and an azadibenzothiophene 5,5-dioxidegroup” each refer to a heteroring having the same backbone as “an indolegroup, a benzoborol group, a benzophosphole group, an indene group, abenzosilole group, a benzogermole group, a benzothiophene group, abenzoselenophene group, a benzofuran group, a carbazole group, adibenzoborole group, a dibenzophosphole group, a fluorene group, adibenzosilole group, a dibenzogermole group, a dibenzothiophene group, adibenzoselenophene group, a dibenzofuran group, a dibenzothiophene5-oxide group, a 9H-fluorene-9-on group, and a dibenzothiophene5,5-dioxide group”, wherein at least one of carbon atoms constitutingthe heteroring is substituted with nitrogen.

For example, the organometallic compound may be one of Compounds 1 to29, but embodiments of the present disclosure are not limited thereto:

T₂ in Formula 1 may be selected from a double bond,*—N[(L₆₃)_(a63)-(R₆₃)]—*′, *—B(R₆₃)—*′, *—P(R₆₃)—*′, *—Si(R₆₃)(R₆₄)—*′,*—Ge(R₆₃)(R₆₄)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′,*—S(═O)₂—*′, *—C(R₆₃)═*′, *═C(R₆₃)—*′, *—C(R₆₃)═C(R₆₄)—*′, *—C(═S)—*′,and *—C≡C—*′. That is, T₂ is neither a single bond nor *—C(R₆₃)(R₆₄)—*′.

Hereinafter, the organometallic compound represented by Formula 1 willbe described with reference to Tables 1 and 2. Data by item in Tables 1and 2 were evaluated with respect to each Compound by using a DTF methodof Gaussian program (structurally optimized at a level of B3LYP,6-31G(d,p)).

TABLE 1 Angle (°) between N-Pt-N in Compound A 80.66 Angle (°) betweenN-Pt-C in Compound 1 94.03 (Corresponding to angle between X₂-M-X₃ inFormula 1)

TABLE 2 Compound HOMO LUMO T₁ S₁ S₁-T₁ Oscillation No. (eV) (eV) (eV)(eV) (eV) strength 1 −4.56 −1.63 2.17 2.38 0.20 0.036 B −4.82 −1.67 2.392.59 0.21 0.0277 C −4.74 −1.65 2.28 2.52 0.23 0.0181 D −4.82 −1.71 2.132.47 0.34 0.0229 E −4.91 −1.64 2.33 2.56 0.23 0.025

The structures of Compounds shown in Tables 1 and 2 are as follows:

T₂ in Formula 1 may be selected from a double bond,*—N[(L₆₃)_(a63)-(R₆₃)]—*′, *—B(R₆₃)—*′, *—P(R₆₃)—*′, *—Si(R₆₃)(R₆₄)—*′,*—Ge(R₆₃)(R₆₄)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′,*—S(═O)₂—*′, *—C(R₆₃)═*′, *═C(R₆₃)—*′, *—C(R₆₃)═C(R₆₄)—*′, *—C(═S)—*′,and *—C≡C—*′. That is, T₂ is neither a single bond nor *—C(R₆₃)(R₆₄)—*′.

As described above, since T₂ in Formula 1 is not a single bond, an anglebetween X₂-M-X₃ in Formula 1 is maintained at an angle, for example, 90°or more, at which the organometallic compound has a planarfour-coordinate structure at which the structural stability thereof ismaintained. Thus, the organometallic compound represented by Formula 1may have an excellent structural stability. Although not limited to aspecific theory, an angle between N—Pt—N of Compound A corresponding toa compound in which T₂ in Formula 1 is a single bond is merely 80.66°,and thus, two pyridine rings in Compound A are twisted. Thus, Compound Amay have a structural instability. However, since an angle betweenN—Pt—C of Compound 1 belonging to Formula 1 (that is, an angle betweenX₂-M-X₃ in Formula 1) is 94.03°, Compound 1 may have a four-coordinatestructure in which the structural stability thereof is maintained (seeTable 1). Therefore, an electronic device, for example, an organiclight-emitting device, which includes the organometallic compoundrepresented by Formula 1, may have a long lifespan.

Also, since i) T₂ in Formula 1 is not *—C(R₆₃)(R₆₄)—*′, and ii) Formula1 includes X₅ defined herein and has an asymmetric structure in which Mand X₄ in Formula 1 are directly connected to each other, theorganometallic compound may have a relatively high oscillation strengthand a relatively small difference between S₁ and T₁. Although notlimited to a specific theory, Compounds B and C corresponding to acompound in which T₂ in Formula 1 is *—C(R₆₃)(R₆₄)—*′ may have a weakoscillation strength because of ineffective electron transition causedby a non-conjugated structure of SP₃ carbon, and Compounds D and Ehaving a symmetrical structure unlike the asymmetric structure ofFormula 1 may have a weak oscillation strength because of thesymmetrical structure of Compounds D and E (see Table 2). Furthermore,Compound D having the symmetrical structure unlike the asymmetricstructure of Formula 1 may have a relatively large difference between Siand T₁ because of the symmetrical structure of Compound D (see Table 2).Therefore, the organometallic compound represented by Formula 1 may havea relatively short decay time, and thus, an electronic device, forexample, an organic light-emitting device, which has the organometalliccompound, may have high luminescent efficiency, high external quantumefficiency, and the like.

For example, the highest occupied molecular orbital (HOMO), lowestunoccupied molecular orbital (LUMO), energy gap, Si energy level, and T₁energy level of Compounds 14 to 29 were evaluated by using a DTF methodof Gaussian program (structurally optimized at a level of B3LYP,6-31G(d,p)), and results thereof are shown in Table 3.

TABLE 3 Compound HOMO LUMO Energy S₁ T₁ No. (eV) (eV) gap (eV) (eV) (eV)14 −4.6121 −1.6458 2.9663 2.3558 2.1754 15 −4.6181 −1.7693 2.8488 2.30612.1618 16 −4.4502 −1.6866 2.7636 2.2278 2.0217 17 −4.4409 −1.8319 2.609 2.1078 1.956  18 −4.5868 −1.7426 2.8442 2.3244 2.1901 19 −4.4156 −1.80712.6085 2.1073 1.9632 20 −4.8194 −1.76   3.0594 2.467  2.2055 21 −4.651 −1.8602 2.7908 2.2809 2.0599 22 −4.526  −1.871  2.655  2.131  1.826  23−4.449  −1.818  2.631  2.113  2.02   24 −4.503  −2.105  2.397  1.896 1.843  25 −4.51   −2.257  2.253  1.788  1.657  26 −4.299  −2.184  2.115 1.622  1.52   27 −4.519  −1.927  2.593  2.072  1.905  28 −4.507  −1.788 2.718  2.194  1.981  29 −4.483  −2.233  2.25   1.786  1.653 

From Table 1, it is confirmed that the organometallic compoundrepresented by Formula 1 has such electric characteristics that aresuitable for use in an electronic device, for example, for use as adopant for an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula1 may be understood by those of ordinary skill in the art by referringto Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for usein an organic layer of an organic light-emitting device, for example,for use as a dopant in an emission layer of the organic layer. Thus,another aspect provides an organic light-emitting device that includes:a first electrode; a second electrode; and an organic layer that isdisposed between the first electrode and the second electrode, whereinthe organic layer includes an emission layer and at least one of theorganometallic compounds represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of anorganic layer including the organometallic compound represented byFormula 1, a low driving voltage, high efficiency, high power, highquantum efficiency, a long lifespan, a low roll-off ratio, and excellentcolor purity.

The organometallic compound represented by Formula 1 may be used betweena pair of electrodes of the organic light-emitting device. For example,the organometallic compound represented by Formula 1 may be included inthe emission layer. In this regard, the organometallic compound may actas a dopant, and the emission layer may further include a host (that is,an amount of the organometallic compound represented by Formula 1 issmaller than an amount of the host).

The expression “(an organic layer) includes at least one oforganometallic compounds” as used herein may include an embodiment inwhich “(an organic layer) includes identical organometallic compoundsrepresented by Formula 1” and an embodiment in which “(an organic layer)includes two or more different organometallic compounds represented byFormula 1.”

For example, the organic layer may include, as the organometalliccompound, only Compound 1. In this regard, Compound 1 may be included inan emission layer of the organic light-emitting device. In one or moreembodiments, the organic layer may include, as the organometalliccompound, Compound 1 and Compound 2. In this regard, Compound 1 andCompound 2 may be included in an identical layer (for example, Compound1 and Compound 2 may both be included in an emission layer).

The first electrode may be an anode, which is a hole injectionelectrode, and the second electrode may be a cathode, which is anelectron injection electrode; or the first electrode may be a cathode,which is an electron injection electrode, and the second electrode maybe an anode, which is a hole injection electrode.

In an embodiment, in the organic light-emitting device, the firstelectrode is an anode, and the second electrode is a cathode, and theorganic layer further includes a hole transport region disposed betweenthe first electrode and the emission layer and an electron transportregion disposed between the emission layer and the second electrode,wherein the hole transport region includes a hole injection layer, ahole transport layer, an electron blocking layer, a buffer layer, or anycombination thereof, and wherein the electron transport region includesa hole blocking layer, an electron transport layer, an electroninjection layer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/ora plurality of layers between the first electrode and the secondelectrode of the organic light-emitting device. The “organic layer” mayinclude, in addition to an organic compound, an organometallic complexincluding metal.

FIG. 1 is a schematic view of an organic light-emitting device 10according to an embodiment. Hereinafter, the structure of an organiclight-emitting device according to an embodiment and a method ofmanufacturing an organic light-emitting device according to anembodiment will be described in connection with FIG. 1. The organiclight-emitting device 10 includes a first electrode 11, an organic layer15, and a second electrode 19, which are sequentially stacked.

A substrate may be additionally disposed under the first electrode 11 orabove the second electrode 19. For use as the substrate, any substratethat is used in general organic light-emitting devices may be used, andthe substrate may be a glass substrate or a transparent plasticsubstrate, each having excellent mechanical strength, thermal stability,transparency, surface smoothness, ease of handling, and waterresistance.

The first electrode 11 may be formed by depositing or sputtering amaterial for forming the first electrode 11 on the substrate. The firstelectrode 11 may be an anode.

The material for forming the first electrode 11 may be selected frommaterials with a high work function to facilitate hole injection. Thefirst electrode 11 may be a reflective electrode, a semi-transmissiveelectrode, or a transmissive electrode. The material for forming thefirst electrode may be, for example, indium tin oxide (ITO), indium zincoxide (IZO), tin oxide (SnO₂), and zinc oxide (ZnO). In one or moreembodiments, magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li),calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) maybe used as the material for forming the first electrode.

The first electrode 11 may have a single-layered structure or amulti-layered structure including two or more layers. For example, thefirst electrode 11 may have a three-layered structure of ITO/Ag/ITO, butthe structure of the first electrode 110 is not limited thereto.

The organic layer 15 is disposed on the first electrode 11.

The organic layer 15 may include a hole transport region, an emissionlayer, and an electron transport region.

The hole transport region may be disposed between the first electrode 11and the emission layer.

The hole transport region may include a hole injection layer, a holetransport layer, an electron blocking layer, a buffer layer, or anycombination thereof.

The hole transport region may include only either a hole injection layeror a hole transport layer. In one or more embodiments, the holetransport region may have a hole injection layer/hole transport layerstructure or a hole injection layer/hole transport layer/electronblocking layer structure, which are sequentially stacked in this statedorder from the first electrode 11.

A hole injection layer may be formed on the first electrode 11 by usingone or more suitable methods selected from vacuum deposition, spincoating, casting, or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, thedeposition conditions may vary according to a compound that is used toform the hole injection layer, and the structure and thermalcharacteristics of the hole injection layer. For example, the depositionconditions may include a deposition temperature of about 100° C. toabout 500° C., a vacuum pressure of about 10⁻⁸ torr to about 10⁻³ torr,and a deposition rate of about 0.01 Angstroms per second (Å/sec) toabout 100 Å/sec. However, the deposition conditions are not limitedthereto.

When the hole injection layer is formed using spin coating, coatingconditions may vary according to the material used to form the holeinjection layer, and the structure and thermal properties of the holeinjection layer. For example, a coating speed may be from about 2,000revolutions per minute (rpm) to about 5,000 rpm, and a temperature atwhich a heat treatment is performed to remove a solvent after coatingmay be from about 80° C. to about 200° C. However, the coatingconditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blockinglayer may be understood by referring to conditions for forming the holeinjection layer.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB,methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzene sulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201 below, anda compound represented by Formula 202 below:

Ar₁₀₁ and Ar₁₀₂ in Formula 201 may each independently be selected from:a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroarylgroup, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, aC₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic condensedpolycyclic group, and a monovalent non-aromatic condensedheteropolycyclic group.

In Formula 201, xa and xb may each independently be an integer from 0 to5, or 0, 1, or 2. For example, xa is 1 and xb is 0, but xa and xb arenot limited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 mayeach independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, apropyl group, a butyl group, a pentyl group, a hexyl group, and so on),or a C₁-C₁₀ alkoxy group (for example, a methoxy group, an ethoxy group,a propoxy group, a butoxy group, a pentoxy group, and so on);

a C₁-C₁₀ alkyl group or a C₁-C₁₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, and a phosphoric acidgroup or a salt thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group, and a C₁-C₁ alkoxy group, but embodiments of thepresent disclosure are not limited thereto.

R₁₀₉ in Formula 201 may be selected from:

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup; and

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, ananthracenyl group, and a pyridinyl group.

According to an embodiment, the compound represented by Formula 201 maybe represented by Formula 201A, but embodiments of the presentdisclosure are not limited thereto:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood byreferring to the description provided herein.

For example, the compound represented by Formula 201, and the compoundrepresented by Formula 202 may include compounds HT1 to HT20 illustratedbelow, but are not limited thereto:

A thickness of the hole transport region may be in a range of about 100Angstroms (Å) to about 10,000 Å, for example, about 100 Å to about 1,000Å. When the hole transport region includes at least one of a holeinjection layer and a hole transport layer, the thickness of the holeinjection layer may be in a range of about 100 Å to about 10,000 Å, andfor example, about 100 Å to about 1,000 Å, and the thickness of the holetransport layer may be in a range of about 50 Å to about 2,000 Å, andfor example, about 100 Å to about 1,500 Å. While not wishing to be boundby theory, it is understood that when the thicknesses of the holetransport region, the hole injection layer, and the hole transport layerare within these ranges, satisfactory hole transporting characteristicsmay be obtained without a substantial increase in driving voltage.

The hole transport region may further include, in addition to thesematerials, a charge-generation material for the improvement ofconductive properties. The charge-generation material may behomogeneously or non-homogeneously dispersed in the hole transportregion.

The charge-generation material may be, for example, a p-dopant. Thep-dopant may be one selected from a quinone derivative, a metal oxide,and a cyano group-containing compound, but embodiments of the presentdisclosure are not limited thereto. Non-limiting examples of thep-dopant are a quinone derivative, such as tetracyanoquinonedimethane(TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane(F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdeniumoxide; and a cyano group-containing compound, such as Compound HT-D1below, but are not limited thereto:

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distanceaccording to a wavelength of light emitted from the emission layer, andthus, efficiency of a formed organic light-emitting device may beimproved.

Then, an emission layer may be formed on the hole transport region byvacuum deposition, spin coating, casting, LB deposition, or the like.When the emission layer is formed by vacuum deposition or spin coating,the deposition or coating conditions may be similar to those applied informing the hole injection layer although the deposition or coatingconditions may vary according to a compound that is used to form theemission layer.

Meanwhile, when the hole transport region includes an electron blockinglayer, a material for the electron blocking layer may be selected frommaterials for the hole transport region described above and materialsfor a host to be explained later.

However, the material for the electron blocking layer is not limitedthereto. For example, when the hole transport region includes anelectron blocking layer, a material for the electron blocking layer maybe mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant mayinclude the organometallic compound represented by Formula 1 or acomposition including the organometallic compound represented by Formula1.

The host may include at least one selected from TPBi, TBADN, ADN (alsoreferred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, Compound H51,and Compound H52:

In one or more embodiments, the host may further include a compoundrepresented by Formula 301 below:

Ar₁₁₁ and Ar₁₁₂ in Formula 301 may each independently be selected from:

a phenylene group, a naphthylene group, a phenanthrenylene group, and apyrenylene group; and

a phenylene group, a naphthylene group, a phenanthrenylene group, and apyrenylene group, each substituted with at least one selected from aphenyl group, a naphthyl group, and an anthracenyl group.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a phenanthrenylgroup, and a pyrenyl group; and

a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenylgroup, each substituted with at least one selected from a phenyl group,a naphthyl group, and an anthracenyl group.

g, h, i, and j in Formula 301 may each independently be an integer from0 to 4, and may be, for example, 0, 1, or 2.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from: aC₁-C₁₀ alkyl group, substituted with at least one selected from a phenylgroup, a naphthyl group, and an anthracenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl, aphenanthrenyl group, and a fluorenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group,a phenanthrenyl group, and a fluorenyl group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthylgroup, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, anda fluorenyl group; and

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the host may include a compound representedby Formula 302 below:

Ar₁₂₂ to Ar₁₂₅ in Formula 302 are the same as described in detail inconnection with Ar₁₁₃ in Formula 301.

Ar₁₂₆ and Ar₁₂₇ in Formula 302 may each independently be a C₁-C₁₀ alkylgroup (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4.For example, k and l may be 0, 1, or 2.

When the organic light-emitting device is a full-color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, and a blue emission layer. Inone or more embodiments, due to a stacked structure including a redemission layer, a green emission layer, and/or a blue emission layer,the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of thedopant may be in a range of about 0.01 parts by weight to about 15 partsby weight based on 100 parts by weight of the host, but embodiments ofthe present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å toabout 1,000 Å, for example, about 200 Å to about 600 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the emission layer is within this range, excellent light-emissioncharacteristics may be obtained without a substantial increase indriving voltage.

Then, an electron transport region may be disposed on the emissionlayer.

The electron transport region may include a hole blocking layer, anelectron transport layer, an electron injection layer, or anycombination thereof.

For example, the electron transport region may have a hole blockinglayer/electron transport layer/electron injection layer structure or anelectron transport layer/electron injection layer structure, but thestructure of the electron transport region is not limited thereto. Theelectron transport layer may have a single-layered structure or amulti-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transportlayer, and the electron injection layer which constitute the electrontransport region may be understood by referring to the conditions forforming the hole injection layer.

When the electron transport region includes a hole blocking layer, thehole blocking layer may include, for example, at least one of BCP,Bphen, and BAlq but embodiments of the present disclosure are notlimited thereto:

A thickness of the hole blocking layer may be in a range of about 20 Åto about 1,000 Å, for example, about 30 Å to about 300 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the hole blocking layer is within these ranges, the hole blockinglayer may have improved hole blocking ability without a substantialincrease in driving voltage.

The electron transport layer may include at least one selected from BCP,Bphen, Alq₃, BAlq, TAZ, and NTAZ:

In one or more embodiments, the electron transport layer may include atleast one of ET1 and ET25, but are not limited thereto:

A thickness of the electron transport layer may be in a range of about100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. Whilenot wishing to be bound by theory, it is understood that when thethickness of the electron transport layer is within the range describedabove, the electron transport layer may have satisfactory electrontransport characteristics without a substantial increase in drivingvoltage.

Also, the electron transport layer may further include, in addition tothe materials described above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complexmay include, for example, Compound ET-D1 (lithium 8-hydroxyquinolate,LiQ) or ET-D2:

The electron transport region may include an electron injection layerthat promotes flow of electrons from the second electrode 19 thereinto.

The electron injection layer may include at least one selected from LiF,NaCl, CsF, Li₂O, and BaO.

A thickness of the electron injection layer may be in a range of about 1Å to about 100 Å, for example, about 3 Å to about 90 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the electron injection layer is within the range described above, theelectron injection layer may have satisfactory electron injectioncharacteristics without a substantial increase in driving voltage.

The second electrode 19 is disposed on the organic layer 15. The secondelectrode 19 may be a cathode. A material for forming the secondelectrode 19 may be selected from metal, an alloy, an electricallyconductive compound, and a combination thereof, which have a relativelylow work function. For example, lithium (Li), magnesium (Mg), aluminum(Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),or magnesium-silver (Mg—Ag) may be used as a material for forming thesecond electrode 19. In one or more embodiments, to manufacture atop-emission type light-emitting device, a transmissive electrode formedusing ITO or IZO may be used as the second electrode 19.

Hereinbefore, the organic light-emitting device has been described withreference to FIG. 1, but embodiments of the present disclosure are notlimited thereto.

Another aspect of the present disclosure provides a diagnosticcomposition including at least one organometallic compound representedby Formula 1.

The organometallic compound represented by Formula 1 provides highluminescent efficiency. Accordingly, a diagnostic composition includingthe organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications includinga diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched saturated aliphatic hydrocarbon monovalent group having 1 to 60carbon atoms. Non-limiting examples thereof include a methyl group, anethyl group, a propyl group, an iso-butyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein refers to a divalentgroup having the same structure as the C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group).Non-limiting examples thereof include a methoxy group, an ethoxy group,and an iso-propyloxy group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup formed by including at least one carbon-carbon double bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group. Examples thereofinclude an ethenyl group, a propenyl group, and a butenyl group. Theterm “C₂-C₆₀ alkenylene group” as used herein refers to a divalent grouphaving the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup formed by including at least one carbon-carbon triple bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group. Examples thereofinclude an ethynyl group, and a propynyl group. The term “C₂-C₆₀alkynylene group” as used herein refers to a divalent group having thesame structure as the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms.Non-limiting examples thereof include a cyclopropyl group, a cyclobutylgroup, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.The term “C₃-C₁₀ cycloalkylene group” as used herein refers to adivalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to amonovalent saturated monocyclic group having at least one heteroatomselected from N, O, P, Si, and S as a ring-forming atom and 1 to 10carbon atoms. Non-limiting examples thereof include a tetrahydrofuranylgroup, and a tetrahydrothiophenyl group. The term “C₁-C₁₀heterocycloalkylene group” as used herein refers to a divalent grouphaving the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to amonovalent monocyclic hydrocarbon group that has 3 to 10 carbon atomshaving at least one carbon-carbon double bond in the ring thereof, andhaving no aromaticity. Non-limiting examples thereof include acyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group.The term “C₃-C₁₀ cycloalkenylene group” as used herein refers to adivalent group having the same structure as the C₃-C₁₀ cycloalkenylgroup.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, P, Si, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one double bond in its ring. Examples of the C₁-C₁₀heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having the samestructure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms, andthe term “C₆-C₆₀ arylene group” as used herein refers to a divalentgroup having a carbocyclic aromatic system having 6 to 60 carbon atoms.Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, anaphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenylgroup, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀arylene group each include two or more rings, the rings may be fused toeach other. The term “C₇-C₆₀ alkylaryl group” as used herein refers to aC₆-C₆₀ aryl group substituted with at least one C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having a carbocyclic aromatic system that has at least oneheteroatom selected from N, O, P, Si, and S as a ring-forming atom, and1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as usedherein refers to a divalent group having a carbocyclic aromatic systemthat has at least one heteroatom selected from N, O, P, Si, and S as aring-forming atom, and 1 to 60 carbon atoms. Non-limiting examples ofthe C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinylgroup, a pyrazinyl group, a pyridazinyl group, a triazinyl group, aquinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroarylgroup and the C₁-C₆₀ heteroarylene group each include two or more rings,the rings may be fused to each other. The term “C₂-C₆₀ alkylheteroarylgroup” as used herein refers to a C₁-C₆₀ heteroaryl group substitutedwith at least one C₁-C₆₀ alkyl group.

The term “C₆-C₆₀ aryloxy group” as used herein indicates —OA₁₀₂ (whereinA₁₀₂ is the C₆-C₆₀ aryl group), the term a “C₆-C₆₀ arylthio group” asused herein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group),and the term “C₇-C₆₀ arylalkyl group” as used herein indicates -A₁₀₄A₁₀₅(wherein A₁₀₄ is the C₆-C₅₉ aryl group and A₁₀₅ is the C₁-C₅₃ alkylgroup).

The term “C₁-C₆₀ heteroaryloxy group” as used herein refers to —OA₁₀₆(wherein A₁₀₆ is the C₁-C₆₀ heteroaryl group), and the term “C₁-C₆₀heteroarylthio group” as used herein indicates —SA₁₀₇ (wherein A₁₀₇ isthe C₁-C₆₀ heteroaryl group).

The term “C₂-C₆₀ heteroarylalkyl group” as used herein refers to-A₁₀₈A₁₀₉ (A₁₀₉ is a C₁-C₅₉ heteroaryl group, and A₁₀₈ is a C₁-C₅₈alkylene group).

The term “monovalent non-aromatic condensed polycyclic group” as usedherein refers to a monovalent group (for example, having 8 to 60 carbonatoms) having two or more rings condensed to each other, only carbonatoms as ring-forming atoms, and having no aromaticity in its entiremolecular structure. Examples of the monovalent non-aromatic condensedpolycyclic group include a fluorenyl group. The term “divalentnon-aromatic condensed polycyclic group” as used herein refers to adivalent group having the same structure as the monovalent non-aromaticcondensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein refers to a monovalent group (for example, having 2 to 60carbon atoms) having two or more rings condensed to each other, aheteroatom selected from N, O, P, Si, and S, other than carbon atoms, asa ring-forming atom, and no aromaticity in its entire molecularstructure. Non-limiting examples of the monovalent non-aromaticcondensed heteropolycyclic group include a carbazolyl group. The term“divalent non-aromatic condensed heteropolycyclic group” as used hereinrefers to a divalent group having the same structure as the monovalentnon-aromatic condensed heteropolycyclic group.

The term “C₅-C₃₀ carbocyclic group” as used herein refers to a saturatedor unsaturated cyclic group having, as a ring-forming atom, 5 to 30carbon atoms only. The C₅-C₃₀ carbocyclic group may be a monocyclicgroup or a polycyclic group.

The term “C₁-C₃₀ heterocyclic group” as used herein refers to asaturated or unsaturated cyclic group having, as a ring-forming atom, atleast one heteroatom selected from N, O, Si, P, and S other than 1 to 30carbon atoms. The C₁-C₃₀ heterocyclic group may be a monocyclic group ora polycyclic group.

At least one substituent of the substituted C₅-C₃₀ carbocyclic group,the substituted C₂-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₇-C₆₀ alkylaryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₇-C₆₀arylalkyl group, the substituted C₁-C₆₀ heteroaryl group, thesubstituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀heteroarylthio group, the substituted C₂-C₆₀ heteroarylalkyl group, thesubstituted C₂-C₆₀ alkylheteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group,an amidino group, a hydrazine group, a hydrazone group, a carboxylicacid group or a salt thereof, a sulfonic acid group or a salt thereof, aphosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkylgroup, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀alkylheteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxygroup, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, aC₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅),—B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉),and

Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independentlybe selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from a C₁-C₆₀ alkyl group and aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a monovalent non-aromatic condensed polycyclicgroup, and a monovalent non-aromatic condensed heteropolycyclic group.

Hereinafter, a compound and an organic light-emitting device accordingto embodiments are described in detail with reference to SynthesisExamples and Examples. However, the organic light-emitting device is notlimited thereto. The wording “B was used instead of A” used indescribing Synthesis Examples means that an amount of A used wasidentical to an amount of B used, in terms of a molar equivalent.

EXAMPLES Synthesis Example 1: Synthesis of Compound 19

Synthesis of Intermediate 19-1

1.20 grams (g) (2.37 millimoles (mmol)) of2,4-di-tert-butyl-6-(6-chloro-4-(3,5-di-tert-butylphenyl)pyridin-2-yl)phenoland 45 milliliters (ml) of toluene were mixed, and 1.12 g (2.37 mmol) ofN-(5-(4-phenylpyridin-2-yl)-[1,1′-biphenyl]-3-yl)-[1,1′-biphenyl]-2-amine,0.068 g (0.12 mmol) of Pd(dba)₂, 0.683 g (7.11 mmol) of NatOBu, and0.097 g (0.24 mmol) of SPhos were added thereto. The mixture was heatedunder reflux at a temperature of 110° C. for 18 hours. After thereaction was completed, the reaction product was concentrated underreduced pressure, mixed with 50 ml of dichloromethane, and filteredthrough diatomaceous earth. The organic layer obtained therefrom wasdried by using magnesium sulfate, distilled under reduced pressure, andpurified by liquid chromatography to obtain 1.43 g (1.51 mmol, yield:64%) of Intermediate 19-1.

LC-MS m/z=944.54 (M+H)⁺.

Synthesis of Compound 19

1.05 g (1.11 mmol) of Intermediate 19-1 was mixed with 50 ml ofbenzonitrile at room temperature, and 0.58 g (1.22 mmol) of PtCl₂(NCPh)₂was added thereto. The mixture was heated under reflux for 14 hours.After completion of the reaction had been confirmed by LCMS, thereaction product was concentrated under reduced pressure and purified byliquid chromatography to obtain 0.92 g (0.81 mmol, yield: 73%) ofCompound 19. The obtained compound was identified by LCMS and ¹H-NMR.

LC-MS m/z=1136.49 (M+H)⁺.

¹H NMR (300 MHz, CD₂Cl₂) δ 9.52 (d, 1H), 8.04 (d, 1H), 7.85 (d, 1H),7.82 (d, 1H), 7.77-7.71 (m, 3H), 7.63-7.48 (m, 9H), 7.42-7.32 (m, 4H),7.25-7.10 (m, 8H), 6.94 (d, 1H), 6.39 (d, 1H), 6.34 (d, 1H), 1.64 (s,9H), 1.33 (s, 27H).

Evaluation Example 1: Evaluation of Photoluminescence (PL) Spectrum andPhotoluminescence Quantum Yield (PLQY)

CBP and Compound 19 were co-deposited on a quartz substrate at a weightratio of 98:2 at a vacuum degree of 10⁻⁷ torr to manufacture a filmhaving a thickness of 40 nanometers (nm).

A photoluminescence (PL) spectrum of the film was measured whilescanning an excitation wavelength at an interval of 10 nm from 320 nm to380 nm by using a Quantaurus-QY Absolute PL quantum yield spectrometer(manufactured by Hamamatsu), including a xenon light source, amonochromator, a photonic multichannel analyzer, and an integratingsphere, PLQY measurement software (Hamamatsu Photonics, Ltd., Shizuoka,Japan). It was confirmed from a PL spectrum measured at an excitationwavelength of 340 nm that Compound 19 had a maximum emission wavelengthof 585 nm, a full width at half maximum (FWHM) of 76.6 nm, andluminescence quantum efficiency of 0.960.

Evaluation Example 2: Measurement of Decay Time

The PL spectrum of the film manufactured according to Evaluation Example1 was evaluated at room temperature by using a time-resolvedphotoluminescence (TRPL) measurement system FluoTime 300 (manufacturedby PicoQuant) and a pumping source PLS340 (manufactured by PicoQuant)(excitation wavelength=340 nm, spectral width=20 nm), a wavelength of amain peak of the PL spectrum was determined, and the number of photonsemitted from the film at the main peak by a photon pulse (pulsewidth=500 picoseconds (ps)) applied to each film by PLS340 was measuredover time based on Time-Correlated Single Photon Counting (TCSPC). Byrepeating the above processes, a sufficiently fittable TRPL curve wasobtained. Then, a decay time T_(decay)(Ex) of the film was obtained byfitting one or more exponential decay functions to a result obtainedfrom the TPRL curve. It was confirmed that the decay time of Compound 19was 2.333 micrometers (μm). A function represented by Equation 10 wasused for the fitting, and a greatest value among T_(decay) valuesobtained from the exponential decay functions used for the fitting wastaken as T_(decay)(Ex). At this time, the same measurement was performedonce more for the same measurement time as that for calculating the TRPLcurve in a dark state (a state in which the pumping signal input to thefilm was blocked) to obtain a baseline or background signal curve. Thebaseline or background curve was used as a baseline for fitting.

$\begin{matrix}{{f(t)} = {\sum\limits_{i = 1}^{n}{A_{i}{\exp \left( {{- t}/T_{{decay},i}} \right)}}}} & {{Equation}\mspace{14mu} 10}\end{matrix}$

Example 1

As an anode, a glass substrate, on which ITO/Ag/ITO were respectivelydeposited to thicknesses of 70 Å/1,000 Å/70 Å, was cut to a size of 50mm×50 mm×0.5 mm (mm=millimeters), sonicated with iso-propyl alcohol andpure water, 5 minutes in each solvent, and then cleaned by exposure toultraviolet rays and ozone for 30 minutes. Then, the glass substrate wasprovided to a vacuum deposition apparatus.

2-TNATA was deposited on the anode to form a hole injection layer havinga thickness of 600 Å, and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl(NPB) was deposited on the hole injection layer to form a hole transportlayer having a thickness of 1,350 Å.

CBP (host) and Compound 19 (dopant) were co-deposited on the holetransport layer at a weight ratio of 98:2 to form an emission layerhaving a thickness of 400 Å, and BCP was deposited on the emission layerto form a hole blocking layer having a thickness of 50 Å. Then, Alq₃ wasdeposited on the hole blocking layer to form an electron transport layerhaving a thickness of 350 Å, LiF was deposited on the electron transportlayer to form an electron injection layer having a thickness of 10 Å,and MgAg was deposited on the electron injection layer at a weight ratioof 90:10 to form a cathode having a thickness of 120 Å, therebycompleting the manufacture of an organic light-emitting device having astructure of ITO/Ag/ITO/2-TNATA (600 Å)/NPB (1,350 Å) /CBP+Compound 19(2 wt %) (400 Å)/BCP (50 Å)/Alq₃ (350 Å)/LiF(10 Å)/MgAg (120 Å).

Comparative Example 1

An organic light-emitting device was manufactured in the same manner asin Example 1, except that Compound shown in Table 4 was used instead ofCompound 19 as a dopant in forming an emission layer

Evaluation Example 3: Evaluation of Characteristics of OrganicLight-Emitting Devices

The driving voltage, luminescent efficiency, external quantum efficiency(EQE), roll-off ratio, maximum emission wavelength, and lifespan (T₉₇)of the organic light-emitting devices manufactured according to Example1 and Comparative Example 1 were evaluated, and results thereof areshown in Table 4. Time-luminance graphs of the organic light-emittingdevices of Example 1 and Comparative Example 1 are shown in FIG. 2. Thisevaluation was performed by using a current-voltage meter (Keithley2400) and a luminance meter (Minolta Cs-1000 Å). The lifespan (T₉₇) (at3,500 nit) indicates an amount of time that lapsed when luminance was97% of initial luminance (100%) (at 3,500 nit). The roll-off ratio wascalculated by using Equation 20.

Roll off={1−(efficiency (at 9,000 nit)/maximum luminescentefficiency)}×100%  Equation 20

TABLE 4 Maximum External Driving Maximum Luminescent External quantumMaximum Voltage luminescent Efficiency Quantum efficiency Roll-offemission Lifespan (V) efficiency (cd/A) Efficiency (%) ratio wavelength(T₉₇) Dopant (at 1500 nit) (cd/A) (at 1500 nit) (%) (at 1500 nit) (%)(nm) (hr) Example 1 Compound 3.59 61.4 58.7 24.4 23.07  4 587 360 19Comparative Compound 4.71 24.0 20.1 19.6 16.10 16 615 250 Example 1 F

Referring to Table 4, it is confirmed that the organic light-emittingdevice of Example 1 has low driving voltage, high luminescentefficiency, high external quantum efficiency, low roll-off ratio, andlong lifespan characteristics, as compared with the organiclight-emitting device of Comparative Example 1.

Since the organometallic compounds have a short decay time, organiclight-emitting devices including such organometallic compounds may haveimproved luminescent efficiency, external quantum efficiency, roll-offratio, and lifespan characteristics. Also, due to excellentphosphorescent luminescent characteristics, such organometalliccompounds may provide a diagnostic composition having high diagnosticefficiency.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present description asdefined by the following claims.

What is claimed is:
 1. An organometallic compound represented by Formula1:

wherein, in Formula 1, M is beryllium (Be), magnesium (Mg), aluminum(Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper(Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium(Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum(Pt), or gold (Au), X₁ to X₄ are each independently C or N, X₅ is O, S,B(R′), N(R′), P(R′), C(R′)(R″), Si(R′)(R″), Ge(R′)(R″), C(═O),B(R′)(R″), N(R′)(R″), or P(R′)(R″), two bonds selected from a bondbetween X₂ and M, a bond between X₃ and M, and a bond between X₄ and Mare each a coordinate bond, and the other thereof is a covalent bond, abond between X₅ and M is a covalent bond, rings CY₁ to CY₄ are eachindependently selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀heterocyclic group, T₁ is selected from a single bond, a double bond,*—N[(L₆₁)_(a61)-(R₆₁)]—*′, *—B(R₆₁)—*′, *—P(R₆₁)—*′, *—C(R₆₁)(R₆₂)—*′,*—Si(R₆₁)(R₆₂)—*′, *—Ge(R₆₁)(R₆₂)—*′, *—S—*′, *—Se—*′, *—O—*′,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₁)═*′, *═C(R₆₁)—*′,*—C(R₆₁)═C(R₆₂)—*′, *—C(═S)—*′, and *—C≡C—*′, T₂ is selected from adouble bond, *—N[(L₆₃)_(a63)-(R₆₃)]—*′, *—B(R₆₃)—*′, *—P(R₆₃)—*′,*—Si(R₆₃)(R₆₄)—*′, *—Ge(R₆₃)(R₆₄)—*′, *—S—*′, *—Se—*′, *—O—*′,*—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₃)═*′, *═C(R₆₃)—*′,*—C(R₆₃)═C(R₆₄)—*′, *—C(═S)—*′, and *—C≡C—*′, T₃ is selected from asingle bond, a double bond, *—N[(L₆₅)_(a65)-(R₆₅)]—*′, *—B(R₆₅)—*′,*—P(R₆₅)—*′, *—C(R₆₅)(R₆₆)—*′, *—Si(R₆₅)(R₆₆)—*′, *—Ge(R₆₅)(R₆₆)—*′,*—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₆₅)═,*═C(R₆₅)—*′, *—C(R₆₅)═C(R₆₆)—*′, *—C(═S)—*′, and *—C≡C—*′, L₆₁, L₆₃, andL₆₅ are each independently selected from a single bond, a substituted orunsubstituted C₅-C₃₀ carbocyclic group, and a substituted orunsubstituted C₁-C₃₀ heterocyclic group, a61, a63, and a65 are eachindependently an integer from 1 to 3, wherein, when a61 is two or more,two or more groups L₆₁ are identical to or different from each other,when a63 is two or more, two or more groups L₆₃ are identical to ordifferent from each other, and when a65 is two or more, two or moregroups L₆₅ are identical to or different from each other, R₆₁ and R₆₂,R₆₃ and R₆₄, and R₆₅ and R₆₆ are each optionally linked via a singlebond, a double bond, or a first linking group to form a substituted orunsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstitutedC₁-C₃₀ heterocyclic group, R₁ to R₄, R₆₁ to R₆₆, R′, and R″ are eachindependently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₇-C₆₀ alkylaryl group, a substituted or unsubstitutedC₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthiogroup, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstitutedC₁-C₆₀ heteroarylthio group, a substituted or unsubstituted C₂-C₆₀heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀alkylheteroaryl group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂),—Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), a1 to a4 are eachindependently an integer from 0 to 20, two of a plurality of neighboringgroups R₁ are optionally linked to form a substituted or unsubstitutedC₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₁-C₃₀heterocyclic group, two of a plurality of neighboring groups R₂ areoptionally linked to form a substituted or unsubstituted C₅-C₃₀carbocyclic group or a substituted or unsubstituted C₁-C₃₀ heterocyclicgroup, two of a plurality of neighboring groups R₃ are optionally linkedto form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or asubstituted or unsubstituted C₁-C₃₀ heterocyclic group, two of aplurality of neighboring groups R₄ are optionally linked to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, at least two neighboringgroups selected from R₁ to R₄ are optionally linked to form asubstituted or unsubstituted C₅-C₃₀ carbocyclic group or a substitutedor unsubstituted C₁-C₃₀ heterocyclic group, * and *′ each indicate abinding site to a neighboring atom, at least one substituent of thesubstituted C₅-C₃₀ carbocyclic group, the substituted C₁-C₃₀heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substitutedC₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, thesubstituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₇-C₆₀alkylaryl group, the substituted C₆-C₆₀ aryloxy group, the substitutedC₆-C₆₀ arylthio group, the substituted C₇-C₆₀ arylalkyl group, thesubstituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, thesubstituted C₂-C₆₀ heteroarylalkyl group, the substituted C₂-C₆₀alkylheteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I,—CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid group or a salt thereof, a sulfonic acid group or a saltthereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkylgroup, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at leastone selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkylgroup, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀alkylheteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉); aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkylgroup, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀alkylheteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, and a monovalent non-aromatic condensed heteropolycyclic group,each substituted with at least one selected from deuterium, —F, —Cl,—Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃—Co cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkylgroup, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀alkylheteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉);and —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and—P(═O)(Q₃₈)(Q₃₉), and Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉are each independently selected from hydrogen, deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from a C₁-C₆₀ alkyl group and aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.
 2. The organometallic compound ofclaim 1, wherein M is Pt, Pd, or Au.
 3. The organometallic compound ofclaim 1, wherein i) X₂ and X₃ are each N, and X₄ is C; or ii) X₂ and X₄are each N, and X₃ is C.
 4. The organometallic compound of claim 1,wherein rings CY₁ to CY₄ are each independently selected from a benzenegroup, a naphthalene group, an anthracene group, a phenanthrene group, atriphenylene group, a pyrene group, a chrysene group, a cyclopentadienegroup, a 1,2,3,4-tetrahydronaphthalene group, a thiophene group, a furangroup, an indole group, a benzoborol group, a benzophosphole group, anindene group, a benzosilole group, a benzogermole group, abenzothiophene group, a benzoselenophene group, a benzofuran group, acarbazole group, a dibenzoborole group, a dibenzophosphole group, afluorene group, a dibenzosilole group, a dibenzogermole group, adibenzothiophene group, a dibenzoselenophene group, a dibenzofurangroup, a dibenzothiophene 5-oxide group, a 9H-fluorene-9-on group, adibenzothiophene 5,5-dioxide group, an azaindole group, an azabenzoborolgroup, an azabenzophosphole group, an azaindene group, an azabenzosilolegroup, an azabenzogermole group, an azabenzothiophene group, anazabenzoselenophene group, an azabenzofuran group, an azacarbazolegroup, an azadibenzoborole group, an azadibenzophosphole group, anazafluorene group, an azadibenzosilole group, an azadibenzogermolegroup, an azadibenzothiophene group, an azadibenzoselenophene group, anazadibenzofuran group, an azadibenzothiophene 5-oxide group, anaza-9H-fluorene-9-on group, an azadibenzothiophene 5,5-dioxide group, apyridine group, a pyrimidine group, a pyrazine group, a pyridazinegroup, a triazine group, a quinoline group, an isoquinoline group, aquinoxaline group, a quinazoline group, a phenanthroline group, apyrrole group, a pyrazole group, an imidazole group, a triazole group,an oxazole group, an isoxazole group, a thiazole group, an isothiazolegroup, an oxadiazole group, a thiadiazole group, a benzopyrazole group,a benzimidazole group, a benzoxazole group, a benzothiazole group, abenzoxadiazole group, a benzothiadiazole group, a5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinolinegroup.
 5. The organometallic compound of claim 1, wherein rings CY₁ toCY₄ are each independently selected from i) a 5-membered ring, ii) a6-membered ring, iii) a condensed ring in which two or more 6-memberedrings are condensed with each other, and iv) a condensed ring in whichat least one 5-membered ring is condensed with at least one 6-memberedring, the 5-membered ring is selected from a cyclopentadiene group, afuran group, a thiophene group, a pyrrole group, a silole group, anoxazole group, an isoxazole group, an oxadiazole group, an isoxadiazolegroup, an oxatriazole group, an isoxatriazole group, a thiazole group,an isothiazole group, a thiadiazole group, an isothiadiazole group, athiatriazole group, an isothiatriazole group, a pyrazole group, animidazole group, a triazole group, a tetrazole group, an azasilolegroup, a diazasilole group, and a triazasilole group, and the 6-memberedring is selected from an adamantane group, a norbornane group, anorbornene group, a cyclohexane group, a cyclohexene group, a benzenegroup, a pyridine group, a pyrimidine group, a pyrazine group, apyridazine group, and a triazine group.
 6. The organometallic compoundof claim 1, wherein T₁ and T₃ are each a single bond, and T₂ is*—N[(L₆₃)_(a63-)(R₆₃)]—*′, *—B(R₆₃)—*′, *—P(R₆₃)—*′, *—Si(R₆₃)(R₆₄)—*′,*—Ge(R₆₃)(R₆₄)—*′, *—S—*′, or *—O—*′.
 7. The organometallic compound ofclaim 1, wherein R₁ to R₄, R₆₁ to R₆₆, R′, and R″ are each independentlyselected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, —SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxygroup; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃,—CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cycloctyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a cyclopentenyl group, acyclohexenyl group, a cycloheptenyl group, a phenyl group, a biphenylgroup, a naphthyl group, a pyridinyl group, and a pyrimidinyl group; acyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctylgroup, an adamantanyl group, a norbornanyl group, a norbornenyl group, acyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, aphenyl group, a biphenyl group, a C₁-C₂₀ alkyl, a phenyl group, anaphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenylgroup, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group,an imidazolyl group, a pyrazolyl group, a thiazolyl group, anisothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, an indolyl group, an indazolyl group, a purinyl group,a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, abenzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group,a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an oxadiazolyl group, a triazinyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; a cyclopentyl group, a cyclohexyl group, acycloheptyl group, a cycloctyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a cyclopentenyl group, acyclohexenyl group, a cycloheptenyl group, a phenyl group, a biphenylgroup, a C₁-C₂₀ alkyl, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,—CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanylgroup, a norbornanyl group, a norbornenyl group, a cyclopentenyl group,a cyclohexenyl group, a cycloheptenyl group, a phenyl group, a biphenylgroup, a C₁-C₂₀ alkyl, a phenyl group, a naphthyl group, a fluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a cinnolinyl group, a carbazolyl group, aphenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, anoxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, an imidazopyridinyl group, and an imidazopyrimidinyl group; and—N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), and Q₁ toQ₉ are independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃,—CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃,—CD₂CD₃, —CD₂CH₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, aniso-propyl group, an n-butyl group, an iso-butyl group, a sec-butylgroup, a tert-butyl group, an n-pentyl group, an iso-pentyl group, asec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthylgroup; and an n-propyl group, an iso-propyl group, an n-butyl group, aniso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, aphenyl group, and a naphthyl group, each substituted with at least oneselected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group. 8.The organometallic compound of claim 1, wherein R₁ to R₄, R₆₁ to R₆₆,R′, and R″ are each independently selected from hydrogen, deuterium, —F,a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-19, and groupsrepresented by Formulae 10-1 to 10-194:

wherein, in Formulae 9-1 to 9-19 and 10-1 to 10-194, “*” indicates abinding site to a neighboring atom, “Ph” indicates a phenyl group, and“TMS” indicates a trimethylsilyl group.
 9. The organometallic compoundof claim 1, wherein a moiety represented by

in Formula 1 is represented by one of Formulae CY1-1 to CY1-25:

wherein, in Formulae CY1-1 to CY1-25, X₁ and R₁ are the same asdescribed in claim 1, X₁₁ is C(R₁₁)(R₁₂), N(R₁₁), O, S, or Si(R₁₁)(R₁₂),R₁₁ to R₁₈ are the same as described in connection with R₁ in claim 1,a16 is an integer from 0 to 6, a14 is an integer from 0 to 4, a13 is aninteger from 0 to 3, a12 is an integer from 0 to 2, *′ indicates abinding site to M in Formula 1, and * indicates a binding site to T₁ inFormula
 1. 10. The organometallic compound of claim 1, wherein a grouprepresented by

in Formula 1 is selected from groups represented by Formulae CY2-1 toCY2-29:

wherein, in Formulae CY2-1 to CY2-29, X₂ and R₂ are the same asdescribed in claim 1, X₂₁ is C(R₂₁)(R₂₂), N(R₂₁), O, S, or Si(R₂₁)(R₂₂),X₂₃ is C(R₂₃) or N, X₂₄ is C(R₂₄) or N, R₂₁ to R₂₈ are the same asdescribed in connection with R₂ in claim 1, a25 is an integer from 0 to5, a24 is an integer from 0 to 4, a23 is an integer from 0 to 3, a22 isan integer from 0 to 2, * indicates a binding site to T₁ in Formula 1,*′ indicates a binding site to M in Formula 1, and *″ indicates abinding site to T₂ in Formula
 1. 11. The organometallic compound ofclaim 1, wherein a group represented by

in Formula 1 is selected from groups represented by Formulae CY3-1 toCY3-29:

wherein, in Formulae CY3-1 to CY3-29, X₃ and R₃ are the same asdescribed in claim 1, X₃₁ is C(R₃₁)(R₃₂), N(R₃₁), O, S, or Si(R₃₁)(R₃₂),X₃₃ is C(R₃₃) or N, X₃₄ is C(R₃₄) or N, R₃₁ to R₃₈ are the same asdescribed in connection with R₃ in claim 1, a35 is an integer from 0 to5, a34 is an integer from 0 to 4, a33 is an integer from 0 to 3, a32 isan integer from 0 to 2, *″ indicates a binding site to T₂ in Formula 1,*′ indicates a binding site to M in Formula 1, and * indicates a bindingsite to T₃ in Formula
 1. 12. The organometallic compound of claim 1,wherein a group represented by

in Formula 1 is selected from groups represented by Formulae CY4-1 toCY4-45:

wherein, in Formulae CY4-1 to CY4-45, X₄ and R₄ are the same asdescribed in claim 1, X₄₁ is C(R₄₁)(R₄₂), N(R₄₁), O, S, or Si(R₄₁)(R₄₂),X₄₃ is C(R₄₃) or N, X₄₄ is C(R₄₄) or N, X₄₅ is C(R₄₅) or N, R₄₁ to R₄₈are the same as described in connection with R₄ in claim 1, a46 is aninteger from 0 to 6, a45 is an integer from 0 to 5, a44 is an integerfrom 0 to 4, a43 is an integer from 0 to 3, a42 is an integer from 0 to2, * indicates a binding site to T₃ in Formula 1, and *′ indicates abinding site to M in Formula
 1. 13. The organometallic compound of claim1, wherein, in Formula 1, a moiety represented by

is selected from groups represented by Formulae CY1(1) to CY1(22), amoiety represented by

is selected from groups represented by Formulae CY2(1) to CY2(30), amoiety represented by

is selected from groups represented by Formulae CY3(1) to CY3(30), and amoiety represented by

is selected from groups represented by Formulae CY4(1) to CY4(50):

wherein, in Formulae CY1(1) to CY1(22), CY2(1) to CY2(30), CY3(1) toCY3(30), and CY4(1) to CY4(50), X₁ to X₄ and R₁ to R₄ are the same asdescribed in claim 1, X₂₁ is C(R₂₁)(R₂₂), N(R₂₁), O, S, or Si(R₂₁)(R₂₂),X₃₁ is C(R₃₁)(R₃₂), N(R₃₁), O, S, or Si(R₃₁)(R₃₂), X₄₁ is C(R₄₁)(R₄₂),N(R₄₁), O, S, or Si(R₄₁)(R₄₂), R_(1a) to R_(1d) are the same asdescribed in connection with R₁ in claim 1, R_(2a) to R_(2c), R₂₁, andR₂₂ are the same as described in connection with R₂ in claim 1, R_(3a)to R_(3c), R₃₁, and R₃₂ are the same as described in connection with R₃in claim 1, R_(4a) to R_(4d), R₄₁, and R₄₂ are the same as described inconnection with R₄ in claim 1, R₁ to R₄, R_(1a) to Rid, R_(2a) toR_(2c), R_(3a) to R_(3c), and R_(4a) to R_(4d) are not hydrogen, inFormulae CY1(1) to CY1(22), *′ indicates a binding site to M in Formula1, and * indicates a binding site to T₁ in Formula 1, in Formulae CY2(1)to CY2(30), * indicates a binding site to T₁ in Formula 1, *′ indicatesa binding site to M in Formula 1, and *″ indicates a binding site to T₂in Formula 1, in Formulae CY3(1) to CY3(30), *″ indicates a binding siteto T₂ in Formula 1, *′ indicates a binding site to M in Formula 1, and *indicates a binding site to T₃ in Formula 1, in Formulae CY4(1) toCY4(50), * indicates a binding site to T₃ in Formula 1, and *′ indicatesa binding site to M in Formula
 1. 14. The organometallic compound ofclaim 1, wherein the organometallic compound is represented by Formula1A:

wherein, in Formula 1 Å, M, X₁ to X₅, and T₁ to T₃ are the same asdescribed in claim 1, Y₁₁ is C(Z₁₁) or N, Y₁₂ is C(Z₁₂) or N, Y₁₃ isC(Z₁₃) or N, Y₁₄ is C(Z₁₄) or N, Y₂₁ is C(Z₂₁) or N, Y₂₂ is C(Z₂₂) or N,Y₂₃ is C(Z₂₃) or N, Y₃₁ is C(Z₃₁) or N, Y₃₂ is C(Z₃₂) or N, Y₃₃ isC(Z₃₃) or N, Y₄₁ is C(Z₄₁) or N, Y₄₂ is C(Z₄₂) or N, Y₄₃ is C(Z₄₃) or N,and Y₄₄ is C(Z₄₄) or N, Z₁₁ to Z₁₄ are the same as described inconnection with R₁ in claim 1, at least two of Z₁₁ to Z₁₄ are optionallylinked to form a C₅-C₃₀ carbocyclic group that is unsubstituted orsubstituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic groupthat is unsubstituted or substituted with at least one R_(10a), Z₂₁ toZ₂₃ are the same as described in connection with R₂ in claim 1, at leasttwo of Z₂₁ to Z₂₃ are optionally linked to form a C₅-C₃₀ carbocyclicgroup that is unsubstituted or substituted with at least one R_(10a) ora C₁-C₃₀ heterocyclic group that is unsubstituted or substituted with atleast one R_(10a), Z₃₁ to Z₃₂ are the same as described in connectionwith R₃ in claim 1, at least two of Z₃₁ to Z₃₄ are optionally linked toform a C₅-C₃₀ carbocyclic group that is unsubstituted or substitutedwith at least one R_(10a) or a C₁-C₃₀ heterocyclic group that isunsubstituted or substituted with at least one R_(10a), Z₄₁ to Z₄₄ arethe same as described in connection with R₄ in claim 1, at least two ofZ₄₁ to Z₄₄ are optionally linked to form a C₅-C₃₀ carbocyclic group thatis unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀heterocyclic group that is unsubstituted or substituted with at leastone R_(10a), and R_(10a) is the same as described in connection with R₁in claim
 1. 15. The organometallic compound of claim 1, wherein theorganometallic compound is one of Compounds 1 to 29:


16. An organic light-emitting device comprising: a first electrode; asecond electrode; and an organic layer between the first electrode andthe second electrode and comprising an emission layer and at least oneof the organometallic compound of claim
 1. 17. The organiclight-emitting device of claim 16, wherein the first electrode is ananode, the second electrode is a cathode, the organic layer furthercomprises a hole transport region between the first electrode and theemission layer and an electron transport region between the emissionlayer and the second electrode, the hole transport region comprises ahole injection layer, a hole transport layer, an electron blockinglayer, or any combination thereof, and the electron transport regioncomprises a hole blocking layer, an electron transport layer, anelectron injection layer, or any combination thereof.
 18. The organiclight-emitting device of claim 16, wherein the emission layer comprisesthe at least one organometallic compound.
 19. The organic light-emittingdevice of claim 18, wherein the emission layer further comprises a host,and an amount of the host is larger than an amount of the organometalliccompound.
 20. A diagnostic composition comprising at least one of theorganometallic compound of claim 1.